Taxometric evidence for a dimensional latent structure of hypnotic suggestibility

Hypnotic suggestibility denotes a capacity to respond to direct verbal suggestions in an involuntary manner. Most research on responsiveness to hypnotic suggestions has focused on highly suggestible individuals but it remains unclear whether these individuals constitute a discrete subgroup (taxon) characterized by a distinct mode of responding from the remainder of the population or whether hypnotic suggestibility is better modelled as a dimensional ability. In this study, we applied taxometric analysis, a method for distinguishing between dimensional and categorical models of a psychological ability, to behavioural and involuntariness subscale scores of the Harvard Group Scale of Hypnotic Susceptibility Scale: Form A (HGSHS:A) in a nonclinical sample (N=584). Analyses of HGSHS:A subscale scores with different a priori taxon base rates yielded consistent evidence for a dimensional structure. These results suggest that hypnotic suggestibility is dimensional and have implications for current understanding of individual differences in responsiveness to direct verbal suggestions.